Joint2D Element

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This command is used to construct a two-dimensional beam-column-joint element object. The two dimensional beam-column joint is idealized as a parallelogram shaped shear panel with adjacent elements connected to its mid-points. The midpoints of the parallelogram are referred to as external nodes. These nodes are the only analysis components that connect the joint element to the surrounding structure.

element Joint2D $eleTag $Nd1 $Nd2 $Nd3 $Nd4 $NdC <$Mat1 $Mat2 $Mat3 $Mat4> $MatC $LrgDspTag


$eleTag unique element object tag
$Nd1 $Nd2 $Nd3 $Nd4 integer tags indicating four external nodes where the joint element is connected to the adjoining beam-column element
$NdC integer tags indicating the central node of beam-column joint (the tag is used to generate the internal node, thus, the node should not exist in the domain or be used by any other node)
$Mat1 uniaxial material tag for interface rotational spring at node 1. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional)
$Mat2 uniaxial material tag for interface rotational spring at node 2. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional)
$Mat3 uniaxial material tag for interface rotational spring at node 3. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional)
$Mat4 uniaxial material tag for interface rotational spring at node 4. Use a zero tag to indicate the case that a beam-column element is rigidly framed to the joint. (optional)
$MatC uniaxial material tag for rotational spring of the central node that describes shear panel behavior
$LrgDspTag an integer indicating the flag for considering large deformations:
0 - for small deformations and constant geometry
1 - for large deformations and time varying geometry
2 - for large deformations ,time varying geometry and length correction


NOTES:

  1. The nodes must be located such that the main chords bisect. The node tags shall be entered in a clockwise or counter-clockwise order.
  2. In the case that the beam-column element is rigidly framed to the joint, the tag for materials $Mat1 to $Mat4 shall be zero.
  3. The shear panel uniaxial material (with the tag $MatC) shall be calibrated for shear-equivalent moment versus shear distortion. In the calibration formulations the shear-equivalent moment is calculated by multiplying the joint average shear stress to the joint panel volume.
  4. The element connects the external nodes to the central node via multi-point constraints, and Joint2D must be used along with either the Penalty or the Transformation constraint handler.

REFERENCES:

Arash Altoontash, 2004, "Simulation and damage models for performance assessment of reinforced concrete beam-column joints", PhD Dissertation, Stanford University, California, USA. [1]



Code Developed by: Arash Altoontash